.header{
    background-color: #f44336;
    text-align: center;
    color: white;
    /* padding-bottom: 10px; */
    padding: 30px 0 0px 0px;
}
.header .header_s{
    display: flex;
}

.header input{
    border: 0;
    height: 50px;
   flex: 1;
   font-size: 16px;
   padding: 10px;  
}
.header button{
   width: 116px;

    font-size: 16px;
    padding: 8px;
    border: 0;
}
ul{
    list-style: none; 
    margin: 0;
    padding: 0;
}
ul li{
    font-size: 18px;
    padding: 12px 40px 12px 40px;
    position: relative;
}
ul li:nth-child(odd){
    background-color: #f9f9f9;
}
ul li:hover{
    cursor: pointer;
    background-color: #ddd;
}
ul li.checked{
    background-color: #888;
    color: white;
    text-decoration: line-through;
}
ul li.checked::before{
    content: "√";
    position: absolute;
    top: 10px;
    left: 15px;
}
ul li span{
    position: absolute;
    top: 0px;
    right: 0px;
    font-size: 18px;
    padding: 12px;
}
ul li span:hover{
background-color:#f44336 ;
}